Holographic dark （bright） screening solitons are predicted in one dimension for a series circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage source. Each crystal can support a holographic screening soliton. The two solitons are known collectively as a separate holographic screening soliton pair with three types： bright-bright, bright-dark and dark-dark. The numerical results show that the two solitons in a soliton pair can affect each other through a light-induced current and their coupling can affect their spatial profiles under the limit in which the optical wave has a spatial extent much less than the width of the crystal.
The holographic focusing effects of light in a carbazole photorefractive film at 632.8 nm wavelength were observed without applying a bias field, owing to the two-beam coupling process in the material. The material was prepared from the mixture of 3-formyl-N-vinylcarbazole (99 wt%) and 2,4,7-trinitro- 9-fluorenone (1 wt%).
FAN Ting ZHANG Yang LIU JinSong CHEN YaKe LIU ShiXiong
In a biased photorefractive crystal, the process of two one-dimensional waves mixing, i.e., the dynamical evolution of both pump beam and signal beam, is traced by numerically solving the coupled-wave equation. Direct simulations show that the propagation and stability of the two beams are completely determined by the system parameters, such as the external bias field, the intensity and the beam waist of the pump beam. By adjusting these parameters, one can control the state of two Gaussian waves mixing. The numerical results are helpful for performing a two-wave mixing experiment.
The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and experimentally.Both the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams increase.In accordance with these results,the state of two Gaussian waves mixing is controllable.
CAI Xin1,2,LIU JinSong1 & WANG ShengLie1 1 Wuhan National Laboratory for Optoelectronics,School of Optoelectronic Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China
